Tuvok's recent unexplained bout of flashbacks appears to coincide with Voyager's passing of a nearby nebula rich in sirillium. Unfortunatley, flashbacks are known to destroy brain tissue in Vulcans, leading to passing. While there is nothing the doctor can do, a mind meld can help Tuvok to find where the flashback is coming from and stop it. Janeway agrees to help Tuvok, and their meld takes them back in time 80 years when Tuvok had served aboard the USS Excelsior, then being captained by Hikaru Sulu.
While chasing a renegade Maquis ship in the Badlands, the USS Voyager and the Maquis ship they are chasing are pulled into a vortex, which sends them instantly to the Delta Quadrant. However, after the destruction of the device that transported them to the Delta Quadrant, the crew of Voyager and the crew of the Maquis ship must join together to fight their way back to their home in the Alpha quadrant, which is many years away. They will meet many foes and many obstacles along the way, but they will also bond as a crew, between those of the Maquis and those of Starfleet.